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Nonlocal hydrodynamic influence on the dynamic contact angle: slip models versus experiment.
Mark C T Wilson1, Jonathan L Summers, Yulii D Shikhmurzaev
1School of Mechanical Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom. m.wilson@leeds.ac.uk
Summary
This study investigates dynamic contact angles in fluid dynamics. Results show that apparent contact angle variations due to hydrodynamic stresses are too small to explain experimental observations, indicating the macroscopic dynamic contact angle is key.
Area of Science:
- Fluid dynamics
- Interface science
- Physical chemistry
Background:
- Dynamic contact angle is crucial for understanding liquid-solid interactions.
- Previous experiments suggest dependence on flow field and geometry.
- The role of hydrodynamic stresses and apparent contact angle requires quantitative examination.
Purpose of the Study:
- To quantitatively assess if hydrodynamic stresses cause apparent contact angle variations.
- To determine if apparent contact angle can explain experimental observations.
- To clarify the nature of the macroscopic dynamic contact angle.
Main Methods:
- Numerical analysis of fluid flow near a moving contact line.
- Calculation of apparent contact angle variations under different flow conditions.
- Comparison of numerical results with experimental data.
Main Results:
- Hydrodynamic stresses induce negligible variations in the apparent contact angle.
- Apparent contact angle changes are insufficient to explain observed experimental effects.
- The macroscopic dynamic contact angle is not solely dependent on contact-line speed.
Conclusions:
- The macroscopic dynamic contact angle is influenced by the flow field and geometry.
- Fluid mechanics boundary conditions must account for these additional dependencies.
- Further research into the physics governing macroscopic dynamic contact angle is warranted.